Pressure responsive fluid flow control valves

ABSTRACT

In one set of embodiments a selected section of tubular stock has its ends welded together to form a pillow-like pressure sensing device with an entry tube and an exit tube each configured to facilitate insertion of the pressure sensing device into the flow path of IV infusate in an IV administration set or system. Fluid pressure in excess of a predetermined amount reconfigures the pressure sensing device from a generally oval configuration to a generally circular configuration to restrict and/or cut off fluid flow into the device while permitting fluid flow from the device to reduce the fluid pressure again reconfiguring the device back to its generally oval configuration and permitting fluid flow into and through the device. In other embodiments a fluid pressure sensing device is formed with a fluid entry chamber and a fluid exit chamber interconnected by a passageway and provided with a piston that reacts to an increase in fluid pressure above a predetermined amount to close off the interconnection between the chambers and fluid flow into the exit chamber. Continued fluid flow from the eit chamber results in a reduction of fluid therein and reopening of the fluid passageway between the chambers.

BACKGROUND OF THE INVENTION

1. Field of the Application

This invention relates to fluid-flow control valves, and moreparticularly to pressure responsive fluid-flow control valvesparticularly adapted for use with Intravenous (IV) infusionapplications.

2. Background Of The Invention—Description Of Prior Art

In the administration of blood, and other fluids, it is sometimesrequired to rapidly increase the flow rate through the IV set toadminister a large or larger volume of IV fluid. This is usually done byapplying pressure to the IV line. One very common means of doing this isby manually squeezing a bladder or bulb in the IV administration set.When that is done, especially if the needle or cannula, or the othervenous access device, cannot accommodate the sudden increase influid-flow, the pressure in the line usually quickly rises to a largeand often dangerous value. Such pressure can easily exceed 20 psi(greater than 1,000 mm Hg) for a brief period. The use of a syringe torapidly infuse fluid in pediatric patients through a small needle canproduce a similar unacceptable pressure. The generally accepted safepressure threshold is about 300 mm Hg, or about 6 psi. If the venousaccess device is not seated properly, this high pressure can be appliedto the patient's veins, and damage the vein and surrounding tissue. Inaddition, some devices in the IV line are not made to withstand such ahigh pressure, and can leak when subjected to this pressure. It is,therefore, desirable and necessary to protect the patient/recipient fromsuch dangerous, and possibly damaging, high pressure.

There are numerous examples of valves for use with IV (intravenous)administration sets and devices. However, valves, such as those shownand described in U.S. Pat. No. 4,146,055 patented on Mar. 27, 1979 to F.E. Ryder et al for “Valve Structure”; U.S. Pat. No. 4,230,300 patentedon Oct. 28,1980 to H. L. Wiltse for “Flow Metering and Shut-Off Valve”;and U.S. Pat. No. 4,332,369 patented on Jan. 1, 1982 to M. Gordon et alfor “Adjustable In-Line Intravenous Valve With Locking Mechanism”;require human intervention to adjust the valves which are in no wayautomatically, and/or otherwise, self-responsive to changes influid-flow pressure. While a valve such as the one shown and describedin U.S. Pat. No. 5,453,097 patented on Sep. 26, 1995 to J. R. Paradisfor “Control of Fluid Flow” may very well permit fluid underunacceptable and dangerous pressures to flow into and out from the valveand from there to a person receiving the fluid infusion. There are alsoshown and described in U.S. Pat. No. 4,256,104 patented on Mar. 17, 1981to A. J. Muetterties et al for “Equipment Sets and System For TheSequential Administration of Medical Liquids At Dual Flow Rates”; U.S.Pat. No. 4,316,460 patented on Feb. 23,1982 to J. N. Genese et al for“Gravitational Flow System For The Sequential Administration of MedicalLiquids”; and in U.S. Pat. No. 4,417,577 patented on Nov. 29, 1983 to J.N. Genese for “Gravitational Flow System For The SequentialAdministration Of Medical Liquids”; but such systems are relativelycomplex and shut down one IV where a second one is turned on and thenact to restrict air-flow when the second IV is finished.

Other valves intended for use with IV administration sets; such as, forexample, those shown and described in U.S. Pat. No. 4,515,588 patentedon May 7,1985 to P. J. Amendolia for “I.V. Flow Regulator” and in U.S.Pat. No. 5,988,211 patented on Nov. 23, 1999 to W. D. Cornell for “I.V.Flow Controller” are provided for flow rate control, and in fact show,describe and teach that there are to be both inlet and outlet fluid-flowchambers and that the pressure in the outlet fluid-flow chamber has toexceed the pressure in the inlet fluid-flow chamber to permit passage offluid to the patient and, as such, unacceptable high fluid-flow pressureentering the inlet chamber will necessitate an even higher and even moreunacceptable fluid-flow pressure to the fluid recipient. On the otherhand a pressure control valve, such as the one shown and described inU.S. Pat. No. 4,787,413 patented to J. M. Saggers on Nov. 29, 1988 for“Pressure Control Valve”; shows, describes and teaches the use of anintermittent on/off air-flow control that incorporates an inflatable sacthat receives a bleed-off from an air duct to operate a plate that, inturn, moves a sealing device away from the opening of the air duct topermit air flow for the end use. The sac, however, when air flowpressure is reduced, returns air flow to the air duct and permitsmovement of the plate, under spring action, to move the sealing deviceback into position blocking the exit of air from the air duct and thusfrom the end use. The air entering the Saggers air-sac does not passthrough the sac but is expelled, when expelled, through the air entryopening to the air sac. As such the valve is obviously only suitable forgasses and not for IV uses. It requires manual adjustment by a rotatableshaft and vents the air to the outside rather than confining it.

SUMMARY OF THE INVENTION

It is therefore an object of this invention to provide new and novelpressure responsive valves.

It is another object of this invention to provide new and novel fluidpressure responsive valves for incorporation into intravenousadministration and infusion sets and systems.

It is yet another object of this invention to provide new and novelfluid pressure responsive valves for incorporation into intravenousadministration sets and systems with relative ease, within thefluid-flow path between the source of the fluid and thepatient/recipient that is to receive the fluid, and permits normal fluidflow with little or no flow restriction.

It is yet still another object of this invention to provide new andnovel pressure responsive valves, primarily for IV use, which arerelatively small in size and volume and which are bio-compatable.

It is yet still another object of this invention to provide new andnovel pressure responsive valves, primarily for IV use, which respond toa predetermined “critical pressure”.

It is yet still another object of this invention to provide new andnovel pressure responsive valves, primarily for IV use, which workpassively without operator adjustment and facilitate a normal fluid flowin safe fluid pressures independent of pressure applied to the fluid.

It is yet still another object of this invention to provide new andnovel pressure responsive valves, primarily for IV use, which respond topressures above a predetermined value to reduce or cut-off inflow offluid to a pressure sensing device while maintaining uninterrupted flowto the recipient.

It is yet still another object of this invention to provide new andnovel pressure responsive valves, primarily for IV use, forincorporation into or with a fluid warmer.

It is still another object of this invention to provide new and novelfluid pressure responsive valves, primarily for IV use, that areconstructed of materials so that the fluid-flow path can be sterilizedand made non-pyrogenic by conventional methods and so that single usethereof is economically feasible.

Other objects of this invention will hereinafter become obvious from thefollowing description of the preferred embodiments of this invention.

The instant pressure response valve (PRV) incorporates a deformablesensor chamber. The geometry of the sensor chamber allows normalfluid-flow to proceed with very low flow restriction when the appliedpressure is well below a predetermined “critical value”. When the fluidpressure is at or exceeds the “critical value” the valve functions bychange of the geometric configuration of the sensing chamber withsufficient force to either overcome the input pressure seen in thechamber or by action of a valve member to crimp fluid flow tubing to thesensing chamber; or by deforming so as to activate a feature in thevalve to cut off fluid flow into the sensor chamber; all withoutinterfering with outflow from the valve to the intended use or user. Thepressure in the valve is automatically reduced below the “criticalvalue” by the continued fluid flow from the sensing chamber, or part ofthe chamber, to once again permit fluid inflow. The pressure responsivevalve (PRV) utilizes a small number of simple plastic components toaccomplish the pressure limiting function, and to maintain very smallsize, and small priming volume. The components contacting the fluid arerelatively easily formed by injection molding or by welding or sealingtubing components, and are presumably sterilizable by conventionalmeans. Example embodiments of simplified valves employing thesemechanisms are shown in the detailed description that follows:

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a partially schematic view of an IV administration set orsystem incorporating and embodying the principles of and the instantinvention;

FIG. 2 is a schematic plan view of a pressure responsive valveincorporating the instant invention;

FIG. 3 is a schematic side view of the pressure responsive valve of FIG.2;

FIG. 4 is a schematic section taken on line 4-4 of FIG. 2;

FIG. 5 is a schematic section taken on line 5-5 of FIG. 2 and showingthe pressure responsive valve as it would be ready to receive fluidand/or as it would receive fluid with a pressure less then a “criticalpressure” for the pressure responsive valve;

FIG. 6 is a schematic section also taken on line 5-5 of FIG. 2 showingthe pressure responsive valve as it would be responding to fluid at orabove the critical pressure;

FIG. 7 is a schematic side view of still another alternative embodimentof pressure responsive valve incorporating the instant invention;

FIG. 8 is a schematic side view of yet another alternative embodiment ofpressure responsive valve incorporating the instant invention;

FIG. 9 is a schematic side view of yet still another alternativeembodiment of pressure responsive valve incorporating the instantinvention;

FIG. 10 is a schematic side view of yet still another alternativeembodiment of pressure responsive valve incorporating the instantinvention;

FIG. 11 is a schematic side view of yet still another alternativeembodiment of pressure responsive valve incorporating the instantinvention;

DESCRIPTION OF THE INVENTIVE EMBODIMENTS

With reference to FIG. 1 there is generally shown at 20 an intravenousIV administration set or system including a reservoir 22, which, by wayof example, may be a pouch or fluid bag containing any of a multiple ofdifferent fluids or infusate 24 appropriate for infusion into arecipient (which could be a person, animal or the like) as will behereinafter explained. An opening 26 facilitates providing a handle 28for reservoir 22 to facilitate carrying and/or hanging of same for use.A tube 40, of conventional construction, connects an output port 42 ofreservoir 22 to an inlet port 44 of a conventional drip chamber 46; theoutlet port 48 of which is connected to a tube 50. A hand pump, bladder,or squeeze pump 56 may be incorporated into IV set 20, to facilitateincreasing pressure on the flow of fluid infusate 24 should that benecessary, by having its input port 58 connected to tube 50 and itsoutput port 60 connected to a tube 62. Tube 62 also connects to aconventional fluid-flow control valve or roller clamp 64 which is, inturn, connected by a tube 66 to an input port 68 of a pressureresponsive fluid-flow valve 70 incorporating the instant invention. Anoutput port 72 of pressure responsive valve 70 is connected by a tube 74to a needle or cannula 76 that is usually inserted into an arm 78 of apatient 80 for delivery of the potential infusate 24 flowing fromreservoir 22.

Tubes 40, 50, 62, 66 and 74 are of conventional construction and use; asare drip chamber 46, bladder 56, and hypodermic needle 76 to apatient/recipient 80. A piece of tape 82 may be utilized to secureneedle 76 in place. Thus it should be clear that tubes 40, 50, 62 and 66and drip chamber 44, bladder 56, valve 64, pressure responsive valve 70,tube 74 and needle 76 together define a fluid-flow path 84 for thedelivery of IV fluid 24 from reservoir 22 to a patient/recipient 78. Itshould be understood that while the various components of IV set 20 havebeen shown as connected and described herein that other suitableconnections may be utilized and additional and/or other components maybe employed for IV set or system 20.

Tube 66 (FIGS. 1-4) extends through input port 68 of pressure responsivevalve 70 and terminates at a “T” tube 90 (FIGS. 1-3, 5 & 6) open at itsends 92 and 94. Pressure responsive valve 70 is fabricated in general asa tube from the same materials as tubes 40, 50, etc. but so as to have asomewhat larger diameter and, for purposes of this specification may beconsidered to have an upper wall 100 (FIGS. 2-6) and a lower wall 102(FIGS. 3-6). A portion of the tube stock from which valve 70 is to befabricated is cut to a selected length and welds 110 (FIGS. 2 & 4) and112 (FIG. 2) are fabricated at respective ends thereof to secure upperwall 100 and lower wall 102 together to form valve 70 into a pillow likeconfiguration. Weld 110 also secures tube 66 in place so that “T” tube90 is properly positioned in pressure responsive valve 70 at a pressureresponsive zone 108 as shown in FIGS. 5 & 6; while weld 112 also securestube 74 (FIG. 1) in place at output port 72 of pressure responsive valve70. Upper wall 100, lower wall 102 are fabricated from plastic materialswhich are transparent or translucent and which posses a predeterminedamount of resilience and flexibility. The sizing and configuration ofwalls 100 and 102 is selected so that when tubes 66 and 72 are in placeand with “T” tube 90 extending as shown from input tube 66 welds 110,112 are applied so that valve 70 assumes said “pillow-like”configuration enclosing a sensing space or chamber 120 within innersurfaces of walls 100 and 102 and welds 110, 112. It should be notedthat the normal, usual or at-rest configuration for valve 70 is an oval(FIG. 5).

When pressure responsive valve 70 is installed in IV set 20 (FIG. 1)fluid-infusate 24 from reservoir 22 will follow fluid-flow path 84entering pressure responsive valve 70 through tube 66, and input port 68and “T” tube 90, exiting valve 70 through exit port 72 and tube 74, toits end use such as by a patient/recipient 78. As long as the pressureexerted by fluid 24 is below a predetermined “critical pressure” valve70 will remain in its oval configuration, with its walls 100 and 102spaced from open ends 92, 94 of “T” tube 90. As such fluid 24 will flowfrom ends 92, 94 of “T” tube 90 into sensing space 120 and therefrom outof valve 70 through its exit port 72 and tube 74. Should the pressurewithin valve 70 rise above the predetermined “critical pressure” fluid24 within sensing space 120 will induce walls 100 102 and 104 of valve70 to assume a circular or near circular configuration as shown in FIG.6. Walls 100 and 102 will approach or even touch ends 92, 94 of “T” tube90 and the flow of fluid 24 from those ends will either stop or becurtailed. However, the fluid 24 already in sensing chamber 120, willcontinue to flow through exit port 72 and thereafter along flow path 84to a recipient/patient 78 because of the fluid pressure in the sensingchamber.

As fluid 24 exits sensing space 120 the fluid pressure therein willautomatically and with no operator intervention be reduced below the“critical limit”. Walls 100, 102 and 104, due to the material andfabrication thereof, will return to their oval disposition (FIG. 5)where they are spaced from ends 92, 94, of “T” tube 90. However, thefluid 24 already in sensing chamber 120 will be at elevated pressure(near the critical pressure) and fluid will continue to flow out ofvalve 70 through exit port 72 and therefore along fluid path 84 to arecipient/patient 78.

With reference to FIG. 7 there is shown an alternative embodiment ofpressure responsive valve 150 that could be incorporated into an IVadministration set or system 152, similar to IV set 20 (FIG. 1), and ata location in IV set 152 similar to that of pressure responsive valve 70of IV set 20. Valve 150 is disposed in a housing 154 sized andconfigured to receive a sensing tube or chamber 156, which is fabricatedfrom materials similar to that of sensing chamber 120 of IV set 20 ofFIG. 1 and with welds 160, 162 proximate the ends of tube 156 so thattube 156 is disposed in an oval, pillow-like, configuration. Weld 160also serves to retain inflow tube or entry 170 in place as an entry intosensing tube or chamber 156; while weld 162 serves to retain outflow orexit tube 172 in place as an exit or outflow from sensing tube 156. Anaction lever 174 is positioned in housing 154 so that its response arm176 is disposed in contact with sensing chamber 156 and so that itspinch arm 178 is disposed in contact with or proximate to a pinch orrestriction zone 180 for inflow tube 170 proximate where it enterssensing chamber 156 but outside sensing chamber 156. A pivot 182 isformed where pinch arm 178 meets response arm 176. The angle at whichpinch arm 178 meets response arm 176, and the relative lengths andwidths of same are selected to provide appropriate coaction betweenaction lever 174 and sensing tube/pillow 156 and commensurate operationof valve 150.

Tube 170 and valve 150 are incorporated into IV set 152 at a suitablelocation so that the outflow from the IV reservoir (not shown) and IVset components that receive that outflow becomes the fluid inflowthrough tube 170 and into sensing chamber 156. As long as the pressureexerted on, or by, such fluid remains under a selected “criticalpressure limit” the flow of the IV fluid will continue through valve 150and outflow tube 172 and thence to the recipient of the IV infusion.Should the pressure on and exerted by the IV fluid reach the “criticallimit” or be in excess thereof, the oval/pillow like configuration ofsensing chamber 156 will become rounder (less oval) and that occurrencewill effect a reaction of sensing chamber 156 with response arm 176 ofaction lever 174 to pivot action lever 174 clockwise (FIG. 7) aboutpivot 182 and move pinch arm 178 against inflow tube 170 atpinch/restriction zone 180 to thus reduce or cut-off inflow of the fluidinto sensing chamber 156. The flow of the fluid that is already insensing chamber 156, however, will continue, under pressure, to flowfrom sensing chamber 156 and out through exit/outflow port 172. As suchthe fluid pressure within and exerted by sensing chamber 156 on responsearm 176 of action lever 174 will diminish permitting the inflow of fluidthrough inflow tube 170 to urge pinch arm 178 to pivot counterclockwiseabout pivot 182 and response arm 176 to follow sensing chamber 156 as itreturns from its reactive circular configuration to its normal ovalconfiguration.

FIG. 8 shows another alternative embodiment of pressure responsive valve200 that could be incorporated into an IV administration set or system202, similar to IV set 20 (FIG. 1), and at a location in IV set 202similar to that of pressure responsive valve 70 of IV set 20. Valve 200is disposed in a housing 204 sized and configured to receive a sensingtube or chamber 206, which is fabricated from materials similar to thatof sensing chamber 120 (FIG. 1) of IV set 20 and sensing chamber 156(FIG. 7) of IV set 152 and with welds 210 and 212 proximate the ends ofchamber 206 so that sensing chamber 206 is disposed in anoval/pillow-like configuration. Weld 210 also serves to retain inflowtube or entry 216 in place as an entry into sensing chamber 206; whileweld 218 serves to retain outflow or exit tube 218 in place as an exitor outflow from sensing chamber 206. A movable piston 220 is positionedin housing 204 in contact with an action wall 222 of sensing chamber 206and for movement towards and away from a pinch/restriction zone 224 ofinflow tube 216. A pinch valve 218 is carried by piston 220 for coactionwith fluid inflow tube 216 at pinch/restriction zone 224.

Inflow tube 216 and pillow-like sensing chamber 206 are incorporatedinto IV set 202 at a suitable location so that outflow from the IVreservoir (not shown) and IV set components that receive fluid therefrom(not shown) becomes the fluid inflow through tube 216 and into sensingchamber 206. As long as the pressure exerted on or by such fluid remainsunder a selected “critical pressure” or “critical limit” the flow of theIV fluid will continue through valve 200 and outflow tube 218 and thenceto the recipient of the IV infusion. Should the pressure on and exertedby the IV fluid reach the “critical pressure limit” or be in excesstherof, the oval/pillow-like configuration of sensing chamber 206becomes rounder (less oval) and that occurance will effect a reaction ofaction wall 222 of sensing chamber 206 with piston 220 to move pinchvalve 228 against and into inflow tube 216 at pinch/restriction zone 224to thus reduce or cut-off inflow of the IV fluid into sensing chamber206. The flow of the IV fluid that is already in sensing chamber 206,however, will continue, under pressure, to flow from sensing chamber 206and out through exit/outflow port 218. As such the fluid pressure withinand exerted by sensing chamber 206 will automatically diminish allowingsensing chamber 206 to return to its oval/pillow-like configuration andits action wall 222 on piston 220 will diminish permitting the inflow ofIV fluid through inflow tube 216 through sensing chamber 206 andtherefrom to the recipient of the infusion.

FIG. 9 shows another alternative embodiment of pressure responsive valve250 that could be incorporated into an IV administration set or system252, similar to IV set 20 (FIG. 1), and at a location in IV set 252similar to that of pressure responsive valve 70 of IV set 20. Valve 250is disposed in a housing 254 sized and configured to receive a sensingtube or chamber 266, which is fabricated from materials similar to thatof sensing chamber 120 (FIG. 1) of IV set 20 and sensing chamber 156(FIG. 7) of IV set 152 and with welds 260 and 262 proximate the ends ofchamber 256 so that sensing chamber 256 is disposed in anoval/pillow-like configuration. Weld 260 also serves to retain inflowtube or entry 270 in place as an entry into sensing chamber 256; whileweld 262 serves to retain outflow or exit tube 272 in place as an exitor outflow from sensing chamber 256. A reaction device 274 is positionedin housing 254 so that a relatively flexible action arm 276 thereof isin contact with an action wall 278 of sensing chamber 256 and formovement towards and away from a pinch/restriction zone 280 of inflowtube 270. A pinch valve 282 is carried by arm 276 for coaction withfluid inflow tube 270 at pinch/restriction zone 280. A pinch piece 284extends from another arm 286 of reaction device 274 towards and forcoaction with pinch valve 282 at pinch/restriction zone 280.

Inflow tube 270 and pillow-like sensing chamber 256 are incorporatedinto IV set 252 at a suitable location so that outflow from the IVreservoir (not shown) and IV set components that receive fluid therefrom(not shown) becomes the fluid inflow through tube 270 and into sensingchamber 256. As long as the pressure exerted on or by such fluid remainsunder a selected “critical pressure or limit” the flow of the IV fluidwill continue through valve 250 and outflow tube 272 and thence to therecipient of the IV infusion. Should the pressure on and exerted by theIV fluid reach the “critical pressure limit” or be in excess therof, theoval/pillow-like configuration of sensing chamber 256 becomes rounder(less oval) and that occurance will effect a reaction of action wall 278of sensing chamber 256 with action arm 276 to move pinch valve 282against and into inflow tube 270 at pinch/restriction zone 280, and incoaction with pinch piece 284 to reduce or cut-off inflow of the IVfluid into sensing chamber 256. The flow of the IV fluid that is alreadyin sensing chamber 256, however, will continue, under pressure, to flowfrom sensing chamber 256 and out through exit/outflow port 272. As suchthe fluid pressure within and exerted by sensing chamber 256 will reduceallowing sensing chamber 256 to return to its oval/pillow-likeconfiguration and its action wall 276 on piston 274 will diminishpermitting the inflow of IV fluid through inflow tube 272 throughsensing chamber 256 and therefrom to the recipient of the infusion.

Another embodiment of pressure responsive valve 300 (FIG. 10) includes ahousing or main body 302 within which there is disposed a valve operator308. Housing 302 and valve operator 308 may be fabricated from materialssimilar to those described above for the other embodiments and may becircular, square, rectangular or of any other suitable horizontal orvertical cross-section configuration. Valve operator 308 includes aflexible silicone diaphragm 310 with a stem 312 extending from itsbottom wall and with stem 312 terminating at a piston-like valve cap316. Diaphragm 310 is seated on a rim 318 that surrounds an inner wall320 of housing 302. A valve seat 330, that surrounds valve stem 312, issupported by a first ledge 332, that extends out from wall 320 ofhousing 302 and a second ledge 334 that is supported by a leg 336 thatextends out from a wall 338 of housing 302. First ledge 332 and secondledge 334 surround but are spaced from valve stem 312 to form a fluidpassageway 340 between a fluid entry or in-flow chamber 342 for valve302 and a fluid outflow or exit chamber 344 for valve 302. A fluidinflow tube 346 is utilized to connect pressure responsive valve 302into an IV set or system, of the type described hereinabove and shown inFIG. 1, through an input port 348 of input chamber 342; while a fluidoutflow tube 350 is utilized to connect pressure responsive valve 302into an IV set or system through an output port 352 of output chamber344 of valve 302. A cap 354, providing a cover for valve 300, includes avent hole 356.

IV fluid entering inflow chamber 342, of pressure responsive valve 300,through tube 346, flows through fluid passage 340 and into outflow orexit chamber 344 and then through outflow tube 350 to either othercomponents of the IV set or system or to the intended recipient of thefluid. Should the pressure of, or exerted by, the fluid exceed a“critical limit pressure” the fluid in outflow chamber 344 will exertsufficient pressure on an underside of diaphragm 310 and move valveoperator 308 along inner wall 320 of housing 302 until valve cap 316seats against valve seat 330 and closes fluid passage 340 and the flowof fluid from input chamber 312 into output chamber 344. Since there areno obstructions to fluid flow out from chamber 344 the fluid will flowfrom chamber 344 through tube 350 and then to other components of the IVset or system and/or then to the recipient of the fluid. As the fluidcontinues to so flow the pressure in chamber 344 will diminish withoutoperator intervention and diaphragm 310 will move along wall 320 ofhousing 302 until valve cap 316 moves away from valve seat 330 to againpermit fluid flow into valve 300 and on to the recipient allautomatically and without operator involvement.

Another embodiment of pressure responsive valve 400 (FIG. 11), similarto but different from the embodiment of FIG. 10, includes a housing ormain body 402 within which there is disposed a valve operator 408.Housing 402 and valve operator 408 may be fabricated from materialssimilar to those described above for the other embodiments and may becircular, square, rectangular or of any other suitable horizontal orvertical cross-section configuration. Valve operator 408 includes aflexible silicone diaphragm 410 with a stem 412 extending from itsbottom wall and with stem 412 terminating at a piston-like valve cap414.

Diaphragm 410 is seated on a rim 418 that surrounds an inner wall 420 ofhousing 402. A tapered valve seat 430, that surrounds valve stem 412, isformed at a lower end of a first ledge 432, that extends out from wall420 of housing 402 and a second ledge 434 that is supported by a leg 436that extends out from a wall 438 of housing 402. First ledge 432 andsecond ledge 434 surround but are spaced from valve stem 412 to form afluid passageway 440 between a fluid entry or in-flow chamber 442 forvalve 402 and a fluid outflow or exit chamber 444 for valve 402. Sides445 of valve stem 412 are tapered down and out for co-action withcorrespondingly tapered valve seat 430. A fluid inflow tube 446, of thetype described for previously described embodiments, is utilized toconnect pressure responsive valve 402 into an IV set or system, of thetype described hereinabove and shown in FIG. 1, through an input port448 of input chamber 442; while a fluid outflow tube 452 of similar sizeand construction is utilized to connect pressure responsive valve 402into an IV set or system through an output port 452 of output chamber444 of valve 402.

IV fluid entering inflow chamber 442, of pressure responsive valve 400,through input port 448, flows through fluid passage 440 and into outflowor exit chamber 444 and then through output port tube 452 to eitherother components of the IV set or system or to the intended recipient ofthe fluid. Should the pressure of, or exerted by, the fluid exceed a“critical limit pressure” the fluid in outflow chamber 444 will exertsufficient pressure on an underside of diaphragm 410 to flex diaphragm410 and move valve cap 416 to seat same against valve seat 430 and closefluid passage 440 and the flow of fluid from input chamber 442 intooutput chamber 444. Since there are no obstructions to fluid flow outfrom chamber 444 the fluid will flow from chamber 444 through port 450and then to other components of the IV set or system and/or then to therecipient of the fluid. As the fluid continues to so flow the pressurein chamber 444 will diminish without operator intervention and diaphragm410 will flex or return back until valve cap 416 moves away from valveseat 430 to again permit fluid flow into valve 400 and on to therecipient all automatically and without operator involvement.

At times an IV warming device 570 (FIG. 12) is employed, as a componentof an IV set or system of the type shown in FIG. 1, with an inflow tube572 to receive fluid flow and an outflow tube 574 to conduct the warmedIV fluid to the next component and/or the recipient of the IV fluid.Warming device 570 includes a case or housing 580 which, in turn,receives a warming mechanism 582 into a seat 584, sized and configuredto receive same. The above described pressure responsive valves may beutilized for such IV sets and systems.

The instant pressure responsive valves (PRV's) operate as a simplecomponents of IV infusion sets and/or systems. The set must be a closedsystem to maintain both sterility of the infusate, and not exposeworkers in the field to unsafe fluids. The PRV's are constructed ofmaterials so that the fluid path is biocompatible-compatible with bloodproducts, and does not leach out any substance which is harmful totissue. Its flow path is readily sterilized and rendered pyrogen free bycommonly used means. It is relatively small, with small priming volume,and capable of being placed in-line in the set. It does not contain anyelectrical components. It operates passively, without requiring the userto make any adjustments or settings and can deliver infusate atunregulated pressures 0 to greater than 1500 mm Hg.

The instant pressure responsive valves allow for sudden increase in flowso long as the applied pressure remains below a “critical pressure limitor value”, (in the range of about 250 to 350 mm Hg for instance). Thevalve has a minimal flow resistance when used at typical IV pressures of50-100 mm Hg, as well as at increased pressures which are below the said“critical value”. The respective valves are formed to provide valves ofsingle “critical pressure limits or values”. It being understood thatvalves with other “critical pressure limits or values” may be fabricateddepending on proposed uses and fluids to be infused.

The present invention can be used as a separate device in an IV set, canbe built into a fluid administration set, or can be integrated into anexisting device. The described PRV embodiments may, for example, bepermanently bonded to the inflow tubing of a device such as the BloodHeater Disposable Set, which is one embodiment of U.S. Pat. No.6,480,257, “Heat Exchanger Usable in Wearable Fluid Heater.” to protectthe device from excessive pressure, or to protect the patient distal tothe device, from excessive pressure. The disclosed PRV's may may befabricated with luer or other fittings for insertion into an IVadministration set or system.

While only certain specific preferred embodiments of the invention havebeen described, it is understood that, many variations thereof arepossible without departing from the principals of this invention asdefined in the following claims.

1. A fluid pressure responsive valve, for insertion into a predeterminedfluid-flow path, and responsive to fluid pressure of a predeterminedamount; comprising: (a) deformable fluid-pressure sensing meansinsertable into a fluid-flow path and responsive to a predeterminedfluid pressure; (b) fluid entry means for said fluid pressure responsivemeans to receive fluid flow from the fluid path and direct the fluidinto said fluid pressure sensing means; and (c) fluid exit means fromsaid fluid pressure sensing means to direct fluid from said fluidpressure sensing means back into said fluid flow path; (d) said fluidpressure sensing means reacts to a change of fluid pressure, within saidfluid pressure sensing means, in excess of said predetermined amount torestrict and/or close-off fluid flow into said fluid pressure sensingmeans while permitting fluid flow from said fluid pressure sensingmeans.
 2. The fluid pressure responsive valve of claim 1; wherein, saidfluid pressure sensing means further reacts to the flow of fluid fromsaid fluid pressure sensing means and a resulting reduction of fluidpressure therein below said predetermined amount to permit the flow offluid into said fluid pressure sensing means.
 3. The fluid pressureresponsive valve of claim 1; wherein, said fluid pressure sensing meansis fabricated from selected materials and so as to be capable of beingin a first configuration when fluid at a fluid pressure less then saidpredetermined amount is to pass into, through and out from said fluidpressure sensing means and of being in a second configuration when fluidat a fluid pressure at or above said predetermined amount is to berestricted and/or cut-off from entering said fluid pressure sensingmeans but permitted to flow from said fluid pressure sensing means. 4.The fluid pressure responsive valve of claim 2; wherein, said firstconfiguration of said fluid pressure sensing means is substantially anoval pillow-like configuration and said second configuration issubstantially a circular configuration.
 5. The fluid pressure responsivevalve of claim 4; wherein, said fluid pressure sensing means includesweld means proximate respective opposite ends thereof that facilitatefabrication of same into said first, oval pillow-like, configurationwhile also permitting said sensing means to re-configure to said secondconfiguration.
 6. The fluid pressure responsive valve of claim of claim4; wherein, said fluid entry means includes a fluid flow directing meansextending part way into said fluid pressure sensing means so that whensaid fluid pressure sensing means is in said first configuration fluidmay flow there into and when said fluid pressure sensing means isreconfiguring to said second configuration fluid flow into said fluidpressure sensing means is restricted and even cut-off from entering saidfluid pressure sensing means.
 7. The fluid pressure responsive valve ofclaim 6; wherein, an inside wall of said fluid pressure sensing meansmoves towards said fluid entry means when said fluid pressure sensingmeans is re-configuring to said second configuration thereof.
 8. Thefluid pressure responsive valve of claim 3; including, (a) housing meanswithin which said fluid pressure sensing means is disposed; and (b)action means positioned in said housing means for co-action with saidfluid pressure sensing means such that upon re-configuration of saidfluid pressure sensing means from said first configuration to saidsecond configuration said fluid pressure sensing means will co-act withsaid action means to cut-off and/or arrest fluid flow into said fluidpressure sensing means.
 9. The pressure responsive valve of claim 8;wherein, said action means includes a pivoting lever with a first leverarm disposed to co-act with said fluid pressure sensing means as itreconfigures between said first configuration thereof and said secondconfiguration thereof, and a second lever arm disposed for co- actionwith said fluid entry means to either permit or restrict and/or cut-offfluid flow therethrough.
 10. The pressure responsive valve of claim 3;wherein, piston means are disposed for co-action with said fluidpressure responsive means as it reconfigures between said firstconfiguration thereof and said second configuration thereof, said pistonmeans including pinch means disposed for co-action with said fluid entrymeans to either permit or restrict and/or cut-off fluid flowtherethrough.
 11. The pressure responsive valve of claim 3; wherein,reaction means are disposed for co-action with said fluid pressureresponsive means as it reconfigures between said first configurationthereof and said second configuration thereof, said reaction meansincluding first and second pinch means between which said fluid entrymeans is disposed and which co-act with said fluid entry means to eitherpermit or restrict and/or cut-off fluid flow therethrough.
 12. Thepressure responsive valve of claim 2; wherein, (a) said fluid sensingmeans includes a first sensing chamber disposed and configured toreceive fluid flow from said fluid entry means and a second sensingchamber disposed and configured to receive fluid from said first chamberand permit fluid flow to exit said pressure sensing means through saidfluid exit means and piston means disposed between said first sensingchamber and said second sensing chamber and co-acting therewith andresponsive to an increase in fluid pressure to or above saidpredetermined pressure to restrict and/or cut-off fluid flow from saidfirst sensing chamber to said second sensing chamber.
 13. The pressureresponsive valve of claim 12; wherein, said piston means includes apiston seat formed on wall means disposed between said first sensingchamber and said second sensing chamber.
 14. The pressure responsivevalve of claim 13; wherein, said piston seat and said piston arefabricated with corresponding tapered surfaces which co-act to restrictand/or cut-off fluid flow from said first sensing chamber to said secondsensing chamber.
 15. A fluid pressure responsive valve, for insertioninto a predetermined infusate flow path, within an infusate heatingdevice, and responsive to fluid pressure of said infusate of apredetermined amount; comprising: (a) deformable infusate pressuresensing means disposed and configured to define a sensing portion ofsaid infusate flow path and responsive to a predetermined fluidpressure; (b) fluid entry means for said infusate pressure sensing meansto receive infusate flow from the infusate flow path and direct theinfusate into said infusate pressure sensing means; and (c) fluid exitmeans from said infustae pressure sensing means to direct fluid fromsaid infusate pressure sensing means back into said infusate flow path.16. A fluid pressure responsive valve, for insertion into apredetermined fluid-flow path, and responsive to fluid pressure of apredetermined amount; comprising: (a) a deformable fluid pressuresensing device for insertion into a fluid-flow path; (b) a fluid entryfor said fluid pressure sensing device; (c) a fluid exit from said fluidpressure sensing device to direct fluid from said fluid pressure sensingdevice back into said fluid flow path; (d) said fluid pressure sensingdevice being configured and constructed to react to a change of fluidpressure, within said fluid pressure sensing device, in excess of saidpredetermined amount to restrict and/or close-off fluid flow into saidfluid pressure sensing device while permitting fluid flow from saidfluid pressure sensing device.
 17. The fluid pressure responsive valveof claim 16; wherein, said fluid pressure sensing device further reactsto the flow of fluid from said fluid pressure sensing device and aresulting reduction of fluid pressure therein below said predeterminedamount to permit the flow of fluid into said fluid pressure sensingdevice.
 18. A method of restricting and/or cutting off fluid flowthrough a fluid flow path in response to a predetermined fluid pressure;comprising: (a) providing a fluid pressure sensing device for insertioninto a fluid-flow path; (b) providing a fluid entry for said fluidpressure sensing device; (c) providing a fluid exit from said fluidpressure sensing device to direct fluid from said fluid pressure sensingdevice back into said fluid flow path; (d) fabricating said fluidpressure sensing device so as to react to a change of fluid pressure,within said fluid pressure sensing device, in excess of saidpredetermined amount to restrict and/or close-off fluid flow into saidfluid pressure sensing device while permitting fluid flow from saidfluid pressure sensing device.
 19. The method of claim 18: including,forming said fluid pressure sensing device from a selected length offlexible tubular material and welding the ends of said selected lengthof tubular material together to form a deformable pressure sensingdevice with a pillow-like configuration.
 20. The method of claim 18;including forming said pressure sensing device with a fluid entrychamber and a fluid exit chamber connected together with a fluidpassageway and providing a valve operating device responsive to a changeof fluid pressure within said fluid entry chamber in excess of saidpredetermined amount to restrict and/or close-off fluid flow from saidfluid entry chamber to said fluid exit chamber while permitting fluidflow from said fluid pressure sensing device.